1. Field of the Invention
The present invention relates to the art of orthopedic cutting tools, and more particularly, to a disposable cutter used for shaping and preparing the femoral bone for implant insertion.
2. Prior Art
Cutting tools used in orthopedic procedures are designed to cut bone and associated tissue matter. Specifically, cutters of the present invention are designed to cut and shape the end of a long bone such as a femur or humerus. Typically, the end of the long bone is cut and shaped for insertion of an implant. As such, these cutters are required to be sterile and sharp. Using a dull cutter generates heat that typically leads to tissue necrosis and results in undesireable patient outcomes. A non-sterile cutter blade typically results in an infected and damaged bone that may lead to other problems for the patient.
Depicted in FIGS. 1 and 1A are images of a prior art bone cutter 10 designed to cut and shape the femoral head 12 of the femur 14. As shown in the figures, the prior art cutter 10 is similar to that of a “hole saw” drill. These prior devices 10 generally comprise a hollow cylinder in which a series of cutting teeth slots 16 are formed within the cylinder wall thickness 18. However, these prior devices 10 do not remove all the bone 14 required to properly fit an implant. Therefore, additional procedures are required to remove this extra bone material 22 and smooth the surface of the bone end 24.
As shown in FIG. 1A, the prior cutter device 10 imparts a channel 20 within the end 24 of the bone 14. This channel 20 and associated bone material 22 proximate the channel 20, must be removed to properly fit the implant (not shown) on the end 24 of the bone 14. Typically, hand tools such as rongeurs are used to remove this extra bone material 22.
Such a bone removal procedure makes it difficult to properly fit an implant over the end 24 of the bone 14. The extra bone material 22 must be intricately removed to produce a smooth surface and ensure that the bone 14 is shaped to meet the exacting dimensions of the implant. If the implant is not properly fit over the end 24 of the bone 14, undesirable implant wear or improper implant operation could result.
In addition to the inefficient bone removal limitations, traditional bone cutters are typically reused multiple times. That is because of their high cost. Such multiple reuses require that the cutter be cleaned and sterilized before each use. Furthermore, over time, as these cutters are used and reused, they become dull, thus requiring resharpening. Therefore the blades of the cutter are required to be resharpened, cleaned and sterilized. However, these resharpening and sterilization processes add additional costs and increase the possibility of infection. In addition, resharpening tends to deform the dimensions of the cutter. These dimensional changes could adversly impact the optimal fit and function of the implant. Furthermore, there is a high likelihood that the cleaning and sterilization process may not remove all possible infection agents such as bacteria, machining lubricants, and the like.
Accordingly, the present invention provides a cost effective single use bone cutter with a novel blade and assembly design that improves cutting efficiency. The enhanced bone cutting and shaping efficiencies of the present invention ensure proper implant fit and reduced implant wear. In addition, the improved bone cutting efficiencies afforded by the present invention, decrease procedural time and minimize patient trauma. Furthermore, the bone cutter of the present invention ensures proper cutter sharpness and cleanliness that promotes optimal patient outcomes.